Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758515AbbGHTYD (ORCPT ); Wed, 8 Jul 2015 15:24:03 -0400 Received: from tex.lwn.net ([70.33.254.29]:48516 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755142AbbGHTXx (ORCPT ); Wed, 8 Jul 2015 15:23:53 -0400 Date: Wed, 8 Jul 2015 13:23:51 -0600 From: Jonathan Corbet To: Eric B Munson Cc: Andrew Morton , Michal Hocko , Vlastimil Babka , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH V3 3/5] mm: mlock: Introduce VM_LOCKONFAULT and add mlock flags to enable it Message-ID: <20150708132351.61c13db6@lwn.net> In-Reply-To: <1436288623-13007-4-git-send-email-emunson@akamai.com> References: <1436288623-13007-1-git-send-email-emunson@akamai.com> <1436288623-13007-4-git-send-email-emunson@akamai.com> Organization: LWN.net MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1026 Lines: 28 On Tue, 7 Jul 2015 13:03:41 -0400 Eric B Munson wrote: > This patch introduces the ability to request that pages are not > pre-faulted, but are placed on the unevictable LRU when they are finally > faulted in. This can be done area at a time via the > mlock2(MLOCK_ONFAULT) or the mlockall(MCL_ONFAULT) system calls. These > calls can be undone via munlock2(MLOCK_ONFAULT) or > munlockall2(MCL_ONFAULT). Quick, possibly dumb question: I've been beating my head against these for a little bit, and I can't figure out what's supposed to happen in this case: mlock2(addr, len, MLOCK_ONFAULT); munlock2(addr, len, MLOCK_LOCKED); It looks to me like it will clear VM_LOCKED without actually unlocking any pages. Is that the intended result? Thanks, jon -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/